<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>

  <style>
    .main{
      width: 100%;
      height: auto;
    }

    .left{
      width: 100px;
      background-color: skyblue;
      position: fixed;
      left: 0;
      top: 0;
      bottom: 0;
    }

    .right{
      width: 150px;
      background-color: darkorange;
      position: fixed;
      right: 0;
      bottom: 0;
      top: 0;
    }

    .middle{
      width: calc(100% - 260px);
      background-color: yellowgreen;
      position: fixed;
      left: 105px;
      top: 0;
      bottom: 0;
    }
  </style>
</head>
<body>
  <div class="main">
    <div class="left"></div>
    <div class="middle"></div>
    <div class="right">
    </div>
  </div>
</body>
</html>